NASHVILLE, Tenn. (AP) — The mother of a man killed in a shooting at a Tennessee Waffle House is now suing the medical center that treated him.

The Tennessean reports the lawsuit filed Tuesday by Shaundelle Brooks says two Vanderbilt University Medical Center doctors placed a breathing tube in her son’s esophagus instead of his lungs, thereby causing his death. Brooks’ son, 23-year-old Akilah DaSilva, was one of four people killed in the 2018 Nashville shooting. His autopsy attributes his death to gunshot wounds.

The lawsuit says Vanderbilt then “concealed or destroyed” an X-ray proving the mistake and has refused to provide the X-ray to Brooks’ attorney, Brian Manookian.

Vanderbilt spokesman John Howser says the medical center denies the allegations. He says state health officials previously investigated DaSilva’s care and found no wrongdoing.